From: Keqian Zhu <zhukeqian1@huawei.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: kvm@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
Kirti Wankhede <kwankhede@nvidia.com>,
Will Deacon <will@kernel.org>,
kvmarm@lists.cs.columbia.edu, Marc Zyngier <maz@kernel.org>,
Joerg Roedel <joro@8bytes.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Alexios Zavras <alexios.zavras@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
Cornelia Huck <cohuck@redhat.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Andrew Morton <akpm@linux-foundation.org>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v3 2/2] vfio/iommu_type1: Fix some sanity checks in detach group
Date: Thu, 28 Jan 2021 23:21:20 +0800 [thread overview]
Message-ID: <5093dace-4b8a-d455-ba16-d0c2da755573@huawei.com> (raw)
In-Reply-To: <20210127164641.36e17bf5@omen.home.shazbot.org>
On 2021/1/28 7:46, Alex Williamson wrote:
> On Fri, 22 Jan 2021 17:26:35 +0800
> Keqian Zhu <zhukeqian1@huawei.com> wrote:
>
>> vfio_sanity_check_pfn_list() is used to check whether pfn_list and
>> notifier are empty when remove the external domain, so it makes a
>> wrong assumption that only external domain will use the pinning
>> interface.
>>
>> Now we apply the pfn_list check when a vfio_dma is removed and apply
>> the notifier check when all domains are removed.
>>
>> Fixes: a54eb55045ae ("vfio iommu type1: Add support for mediated devices")
>> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
>> ---
>> drivers/vfio/vfio_iommu_type1.c | 33 ++++++++++-----------------------
>> 1 file changed, 10 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
>> index 161725395f2f..d8c10f508321 100644
>> --- a/drivers/vfio/vfio_iommu_type1.c
>> +++ b/drivers/vfio/vfio_iommu_type1.c
>> @@ -957,6 +957,7 @@ static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
>>
>> static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
>> {
>> + WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list));
>> vfio_unmap_unpin(iommu, dma, true);
>> vfio_unlink_dma(iommu, dma);
>> put_task_struct(dma->task);
>> @@ -2250,23 +2251,6 @@ static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
>> }
>> }
>>
>> -static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu)
>> -{
>> - struct rb_node *n;
>> -
>> - n = rb_first(&iommu->dma_list);
>> - for (; n; n = rb_next(n)) {
>> - struct vfio_dma *dma;
>> -
>> - dma = rb_entry(n, struct vfio_dma, node);
>> -
>> - if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)))
>> - break;
>> - }
>> - /* mdev vendor driver must unregister notifier */
>> - WARN_ON(iommu->notifier.head);
>> -}
>> -
>> /*
>> * Called when a domain is removed in detach. It is possible that
>> * the removed domain decided the iova aperture window. Modify the
>> @@ -2366,10 +2350,10 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>> kfree(group);
>>
>> if (list_empty(&iommu->external_domain->group_list)) {
>> - vfio_sanity_check_pfn_list(iommu);
>> -
>> - if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
>> + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) {
>> + WARN_ON(iommu->notifier.head);
>> vfio_iommu_unmap_unpin_all(iommu);
>> + }
>>
>> kfree(iommu->external_domain);
>> iommu->external_domain = NULL;
>> @@ -2403,10 +2387,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>> */
>> if (list_empty(&domain->group_list)) {
>> if (list_is_singular(&iommu->domain_list)) {
>> - if (!iommu->external_domain)
>> + if (!iommu->external_domain) {
>> + WARN_ON(iommu->notifier.head);
>> vfio_iommu_unmap_unpin_all(iommu);
>> - else
>> + } else {
>> vfio_iommu_unmap_unpin_reaccount(iommu);
>> + }
>> }
>> iommu_domain_free(domain->domain);
>> list_del(&domain->next);
>> @@ -2488,9 +2474,10 @@ static void vfio_iommu_type1_release(void *iommu_data)
>> struct vfio_iommu *iommu = iommu_data;
>> struct vfio_domain *domain, *domain_tmp;
>>
>> + WARN_ON(iommu->notifier.head);
>
> I don't see that this does any harm, but isn't it actually redundant?
> It seems vfio-core only calls the iommu backend release function after
> removing all the groups, so the tests in _detach_group should catch all
> cases. We're expecting the vfio bus/mdev driver to remove the notifier
> when a device is closed, which necessarily occurs before detaching the
> group. Thanks,
>
> Alex
Hi Alex,
Sorry that today I was busy at sending the smmu HTTU based dma dirty log tracking.
I will reply you tomorrow. Thanks!
Keqian.
>
>> +
>> if (iommu->external_domain) {
>> vfio_release_domain(iommu->external_domain, true);
>> - vfio_sanity_check_pfn_list(iommu);
>> kfree(iommu->external_domain);
>> }
>>
>
> .
>
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next prev parent reply other threads:[~2021-01-28 15:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 9:26 [PATCH v3 0/2] vfio/iommu_type1: some fixes Keqian Zhu
2021-01-22 9:26 ` [PATCH v3 1/2] vfio/iommu_type1: Populate full dirty when detach non-pinned group Keqian Zhu
2021-01-22 9:26 ` [PATCH v3 2/2] vfio/iommu_type1: Fix some sanity checks in detach group Keqian Zhu
2021-01-27 23:46 ` Alex Williamson
2021-01-28 15:21 ` Keqian Zhu [this message]
2021-01-29 7:47 ` Keqian Zhu
2021-02-02 17:21 ` [PATCH v3 0/2] vfio/iommu_type1: some fixes Alex Williamson
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